Light emitting devices and light emitting bulbs including the same

ABSTRACT

Filament type light emitting devices are disclosed. One of the light emitting devices includes a non-conductive transparent substrate, one or more light emitting diode chips arrayed above the upper surface of the non-conductive transparent substrate and each including input and output ends extending toward the non-conductive transparent substrate, and conductive transparent connection portions formed on the upper surface of the non-conductive transparent substrate and electrically connected to the input and output ends. Light transmitting regions are provided without reflectors in the vicinity of the input and output ends between the non-conductive transparent substrate and the light emitting diode chips. Thus, light is emitted backward from the light emitting diode chips through the light transmitting regions and the non-conductive transparent substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119(a) toKorean Patent Application No. 10-2016-0047607 filed in the Republic ofKorea on Apr. 19, 2016, Korean Patent Application No. 10-2016-0047638filed in the Republic of Korea on Apr. 19, 2016, and Korean PatentApplication No. 10-2016-0062712 filed in the Republic of Korea on May23, 2016, all of which are hereby incorporated by reference in theirentireties.

BACKGROUND Field of the Disclosure

The present invention relates to filament type light emitting devicesand light emitting bulbs including the same.

Discussion of the Related Art

Light emitting bulbs have been developed in which a plurality offilament type light emitting devices are placed in a light transmittingglobe. Each of the light emitting devices includes an elongated packageand a plurality of light emitting diode chips mounted on the package.For both forward and backward light emission, light emitting devicesarranged such that light is emitted forward may be connected in seriesto light emitting devices arranged such that light is emitted backward.

However, since each of the light emitting devices emits light in onlyone direction, an increased number of the light emitting devices arerequired to distribute light at desired angles.

An existing flip-chip type light emitting diode chip includes a sapphiresubstrate formed on the epilayers and input and output ends formed underthe epilayers. Each of the input and output ends includes an electrodepad and a solder bump. The underside of the epilayers is covered with areflective layer from which light is reflected upward. The reflectivelayer makes it difficult to apply the flip-chip type light emittingdiode chip to a filament type light emitting device where backward lightemission is required.

SUMMARY

One object of the present invention is to provide a light emittingdevices including a structure capable of emitting light forward andbackward from flip-chip type light emitting diode chips.

Another object of the present invention is to provide light emittingbulbs that use light emitting devices including a structure capable ofemitting light forward and backward from flip-chip type light emittingdiode chips, achieving light distribution at much wider angles.

According to one aspect of the present invention, a light emittingdevice includes a non-conductive transparent substrate, one or morelight emitting diode chips mounted above the upper surface of thenon-conductive transparent substrate and each including input and outputends extending toward the non-conductive transparent substrate, andconductive transparent connection portions formed on the upper surfaceof the non-conductive transparent substrate and electrically connectedto the input and output ends wherein light transmitting regions areprovided in the vicinity of the input and output ends between thenon-conductive transparent substrate and the light emitting diode chipsand light is emitted backward from the light emitting diode chipsthrough the light transmitting regions and the non-conductivetransparent substrate.

According to a further aspect of the present invention, a light emittingdevice includes an elongated non-conductive transparent substrate, aninput terminal arranged on one side of the non-conductive transparentsubstrate, an output terminal arranged on the other side of thenon-conductive transparent substrate, n light emitting diode chipsarrayed above the non-conductive transparent substrate and each havinginput and output ends, and connection means formed on the non-conductivetransparent substrate to connect the n light emitting diode chips inseries wherein the connection means includes a first connection portionthat connects the input terminal to the input end of the first lightemitting diode chip and is made of a conductive transparent material.

According to another aspect of the present invention, a light emittingdevice includes an elongated first substrate, an elongated secondsubstrate spaced apart from and parallel to the first substrate,connection means provided between the first substrate and the secondsubstrate and made of a conductive material, and n light emitting diodechips mounted above both the first substrate and the second substrateand electrically interconnected through input and output ends connectedto the connection means wherein gaps are formed between the firstsubstrate and the second substrate to allow light from the n lightemitting diode chips to pass therethrough.

The light emitting devices of the present invention are characterized bya structure in which light is transmitted backward through the bottomsof flip-chip type light emitting diode chips, each of which has inputand output ends, and a substrate connected to the input and output ends.Due to this structure, the light emitting devices can emit a largeamount of light in both forward and backward directions. The lightemitting devices are advantageous for use in light emitting bulbs.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a view for explaining a general light emitting bulb;

FIG. 2 is a plan cross-sectional view for explaining a filament typelight emitting device for a light emitting bulb according to a firstembodiment of the present invention;

FIG. 3 is a side cross-sectional view illustrating the filament typelight emitting device of FIG. 2;

FIG. 4 is an enlarged plan cross-sectional view of the filament typelight emitting device according to the first embodiment of the presentinvention;

FIG. 5 is an enlarged side cross-sectional view of the filament typelight emitting device according to the first embodiment of the presentinvention;

FIG. 6 is a partial side cross-sectional view of a filament type lightemitting device according to a second embodiment of the presentinvention;

FIG. 7 is a partial side cross-sectional view of a filament type lightemitting device according to a third embodiment of the presentinvention;

FIG. 8 is a view for explaining a filament type light emitting deviceaccording to a fourth embodiment of the present invention;

FIG. 9 is a view for explaining a filament type light emitting deviceaccording to a fifth embodiment of the present invention;

FIG. 10 is a perspective view illustrating a light emitting deviceaccording to a sixth embodiment of the present invention;

FIG. 11 is a perspective view illustrating a state in which anencapsulant is removed from the light emitting device according to thesixth embodiment of the present invention;

FIG. 12 is a plan view illustrating the light emitting device accordingto the sixth embodiment of the present invention;

FIG. 13 illustrates cross-sectional views taken along lines (a) I-I′ and(b) II-II′ of FIG. 12;

FIG. 14 is a perspective view illustrating a light emitting deviceaccording to a seventh embodiment of the present invention; and

FIG. 15 is a plan view illustrating the light emitting device of FIG.14.

DETAILED DESCRIPTION

Preferred embodiments of the present invention will now be describedwith reference to the accompanying drawings.

FIG. 1 is a view for explaining a general light emitting bulb.

Referring to FIG. 1, the light emitting bulb includes a base 2000, alight transmitting globe 3000 coupled to a front opening of the base2000, leads 4200 and 4400 for power supply provided in the base 2000 andextending to a space defined by the light transmitting globe 3000, and aplurality of light emitting devices 1000 arranged inside the lighttransmitting globe 3000 and receiving power through the leads 4200 and4400 to emit light.

The base 2000 is removably fitted into a socket for power supply andincludes electrodes electrically connected to the socket. For connectionto the socket, the base 2000 has an externally threaded portion screwedinto an internally threaded portion of the socket.

The light transmitting globe 3000 is divided into front and rear regionsbased on the location of the light emitting devices 1000. The front andrear regions of the light transmitting globe 3000 are made of the sametransparent material, taking into consideration the characteristics ofthe light emitting devices 1000 that can emit light not only in thebackward direction but also in the forward direction, which will beexplained below. The light transmitting globe 3000 includes aspherically shaped portion 3200 and a neck portion 3400 integrated withthe spherically shaped portion 3200 at the rear of the sphericallyshaped portion 3200 and coupled to the base.

The leads 4200 and 4400 stand upright in the base 2000 and extend to aspace defined by the light transmitting globe 3000. The leads 4200 and4400 function to supply power to the light emitting devices 1000 andfirmly support the light emitting devices 1000. The functions of theleads will be explained in more detail. The light emitting devices 1000are arranged at angles with respect to each other and are connected inseries. One of the leads 4200 and 4400 is connected to a lead terminalprovided at the power input side of the first light emitting device ofthe light emitting devices 1000 arranged in series and the other lead4400 is connected to a lead terminal provided at the power output sideof the last light emitting device 1000 of the light emitting devices1000 arranged in series. The light emitting devices 1000 have sufficientstiffness to maintain their original shape. The light emitting devices1000 are interconnected and connected to the leads 4200 and 4400 throughoutwardly extending terminals 1001 and 1002 protruding from both sidesthereof (see FIGS. 2 and 5). With this arrangement, the light emittingdevices 1000 can receive power.

First Embodiment

FIGS. 2 to 5 illustrate a light emitting device according to a firstembodiment of the present invention.

Referring to FIGS. 2 to 5, the light emitting device 1000 includes anelongated non-conductive transparent substrate 1100, an input terminal1210 arranged on one side of the non-conductive transparent substrate1100, an output terminal 1220 arranged on the other side of thenon-conductive transparent substrate 1100, n light emitting diode chips1300 arrayed above the non-conductive transparent substrate 1100 andeach having an input end 1320 and an output end 1340, and connectionmeans 1400 formed on the non-conductive transparent substrate 1100 toconnect the n light emitting diode chips 1300 in series. The lightemitting device 1000 may further include an elongated light transmittingencapsulant 1500 that covers the light emitting diode chips 1300 and thenon-conductive transparent substrate 1100 above which the light emittingdiode chips 1300 are mounted, while allowing exposure of outwardlyextending terminals 1001 and 1002 protruding from both sides of thenon-conductive transparent substrate. The light transmitting encapsulant1500 may be formed by molding a transparent resin and may include awavelength conversion material, for example, a fluorescent material,that acts in concert with at least some of the light emitting diodechips 1300, particularly blue light emitting diode chips, to producewhite light.

The connection means 1400 formed on the non-conductive transparentsubstrate 1100 is transparent and conductive. The connection means 1400includes a first conductive transparent connection portion 1401connecting the input terminal 1210 to the input end 1320 of the firstlight emitting diode chip 1301, a second conductive transparentconnection portion 1402 spaced apart from the first conductivetransparent connection portion 1401 and connecting the output end 1340of the first light emitting diode chip 1301 to the input end 1320 of thesecond light emitting diode chip 1302, an (n+1)^(th) conductivetransparent connection portion 140 n+1 connecting the output terminal1220 to the output end 1340 of the n^(th) light emitting diode chip 130n, and an n^(th) conductive transparent connection portion 140 n spacedapart from the (n+1)^(th) conductive transparent connection portion 140n+1 and connected to the input end 1320 of the n^(th) light emittingdiode chip 130 n. The connection means 1400 includes intermediateconductive transparent connection portions 1403, . . . , each of whichconnects the two adjacent light emitting diode chips 1300.

As previously mentioned, all conductive transparent connection portions,including the first, second, n^(th), and (n+1)^(th) conductiveconnection portions, are spaced apart from each other and are in theform of conductive transparent thin films, which will be explained inmore detail below.

The non-conductive transparent substrate 1100 has flat upper and lowersurfaces and is elongated in the lengthwise direction thereof. Thenon-conductive transparent substrate 1100 is made of a non-conductivetransparent material, such as transparent plastic, glass or quartz. Theinput terminal 1210 is formed on one side of the upper surface of thenon-conductive transparent substrate 1100, more specifically, on theupper surface of one end of the non-conductive transparent substrate1100, and is made of a conductive metal material. The input terminaloutput terminal 1220 is formed on the other side of the upper surface ofthe non-conductive transparent substrate 1100, more specifically, on theupper surface of the other end of the non-conductive transparentsubstrate 1100, and is made of a conductive metal material. The inputterminal 1210 and the output terminal 1220 are connected to theoutwardly extending terminals 1001 and 1002 protruding outward from thenon-conductive transparent substrate 1100, respectively. The outwardlyextending terminals 1001 and 1002 are connected to the leads 4200 and4400 (see FIG. 1), respectively.

Before formation of the input terminal 1210 and the output terminal1220, the connection means 1400 is provided on the upper surface of thenon-conductive transparent substrate 1100. The connection means 1400 isformed by patterning a conductive transparent film. For example, theconnection means 1400 may be formed by forming a conductive transparentfilm over the entire upper surface of the non-conductive transparentsubstrate 1100 and etching the conductive transparent film through amask. Alternatively, the connection means 1400 may be formed byarranging a patterned mask on the non-conductive transparent substrate1100 and forming a conductive transparent film on the mask. Theconductive transparent film may be a metal oxide film for a transparentelectrode, such as an indium tin oxide (ITO) film, but is preferablymade of a metal material including at least one of Ni, Au, Pt, Pd, andW. The metal material is formed to a thickness of 10 μm or less on thenon-conductive transparent substrate.

The n light emitting diode chips 1300 are arrayed in a line above theupper surface of the non-conductive transparent substrate 1100 betweenthe input terminal 1210 and the output terminal 1220. The input end 1320and the output end 1340 of each of the n light emitting diode chips 1300include electrode pads 1321 and 1341 and/or bumps 1322 and 1342,respectively, that extend toward the non-conductive transparentsubstrate 1100.

The n light emitting diode chips 1300 are flip-chip type light emittingdiode chips and are mounted above the non-conductive transparentsubstrate 1100 by flip-chip bonding. As a result of the mounting, the nlight emitting diode chips 1300 are connected to the correspondingconductive transparent connection portions of the connection means 1400formed using a conductive transparent film on the non-conductivetransparent substrate 1100 such that they are connected in series toform a circuit. In this embodiment, the conductive transparentconnection portions 1401, 1402, 1403, . . . , 140 n, and 140 n+1 connectthe input terminal to the first light emitting diode chip, connect theoutput terminal to the last light emitting diode chip, and the adjacentintermediate light emitting diode chips to each other. This connectioneliminates the need for the use of bonding wires, unlike series circuitconnection of conventional lateral type light emitting diode chips.

Only a vacant light transmitting region aa exists except the input end1320 and the output end 1340 between the lower surface of each of thelight emitting diode chips 1300 and the upper surface of thenon-conductive transparent substrate 1100. Thus, despite their flip-chiptype, the light emitting diode chips 1300 can emit light even in thebackward direction without the need to provide additional reflectors inthe direction toward the non-conductive transparent substrate 1100. Morespecifically, the light emitting diode chips 1300 can emit light notonly in the forward direction without loss but also in the backwarddirection through the non-conductive transparent substrate 1100. Forexample, 30% of the total amount of light from the light emitting diodechips 1300 is emitted in the forward direction where a sapphiresubstrate is placed and 70% of the total amount of light is emitted inthe backward direction through the non-conductive transparent substrate1100.

In this embodiment, each of the n light emitting diode chips 1300includes a light transmitting substrate 1311, a first conductivity typesemiconductor layer 1312, an active layer 1313, and a secondconductivity type semiconductor layer 1314 in this order from top tobottom. A portion of the second conductivity type semiconductor layer1314 is connected to the first electrode pad 1321. A portion of thefirst conductivity type semiconductor layer 1312 is opened by mesaetching and is connected to the second electrode pad 1341.

The light transmitting substrate 1311 is used for the growth of thefirst conductivity type semiconductor layer 1312, the active layer 1313,and the second conductivity type semiconductor layer 1314. The firstconductivity type semiconductor may be a gallium nitride-based layer.More preferably, the light transmitting substrate 1311 is a transparentsapphire substrate. The first conductivity type semiconductor layer 1312and the second conductivity type semiconductor layer 1314 may be ann-type semiconductor layer and a p-type semiconductor layer,respectively. The active layer 1313 may include multi-quantum wells.

The first electrode pad 1321 and the second electrode pad 1341 areconnected to the conductive transparent connection portion 1401, 1401,1402, 1403, . . . , 140 n or 140 n+1 on the non-conductive transparentsubstrate 1100 through the first bump 1322 and the second bump 1342,respectively.

It is preferred that the input terminal 1210 includes a metal basematerial 1211 including at least one of Ag, Au, Cu, and Al and areflective material film coated on the metal base material. Likewise, itis preferred that the output terminal 1220 includes a metal basematerial including at least one of Ag, Au, Cu, and Al and a reflectivematerial film coated on the metal base material.

The light emitting device 1000 is fabricated by the following procedure.First, the non-conductive transparent substrate 1100 is prepared. Ametal material including Ni, Au, Pt, Pd or W or a metal oxide, such asITO, is deposited to a thickness of 10 μm or less on the non-conductivetransparent substrate 1100 to form a conductive transparent film. Then,the conductive transparent film is etched to form the connection means1400 including conductive transparent connection portions 1401, 1402,1403, . . . , 140 n, and 140 n+1 on the non-conductive transparentsubstrate 1100. Alternatively, the connection means 1400 includingconductive transparent connection portions 1401, 1402, 1403, . . . , 140n, and 140 n+1 may be formed by forming a patterned mask on thenon-conductive transparent substrate 1100 and microdepositing atransparent metal oxide or a metal thereon. An E-beam or sputteringprocess may be used for the formation of the connection means 1400.

Next, the input terminal 1210 and the output terminal 1220 are arrangedon the non-conductive transparent substrate 1100 such that they areelectrically connected in series with the light emitting diode chips1300 through the conductive transparent connection portions 1401, 1402,1403, . . . , 140 n, and 140 n+1. With this arrangement, the inputterminal 1210 is connected to the input end 1320 of the first lightemitting diode chip 1301 through the first conductive transparentconnection portion 1401, the output end 1340 of the first light emittingdiode chip 1301 is connected to the input end 1320 of the second lightemitting diode chip 1302 through the second conductive transparentconnection portion 1402, the output terminal 1220 is connected to theoutput end 1340 of the n^(th) light emitting diode chip 130 n throughthe (n+1)^(th) conductive transparent connection portion 140 n+1, andthe n^(th) conductive transparent connection portion 140 n is connectedto the input end 1320 of the n^(th) light emitting diode chip 130 n. Inaddition, the other adjacent light emitting diode chips 1300 areconnected to each other through the corresponding conductive transparentconnection portions.

The first conductive transparent connection portion 1401 includes aportion adapted to the input terminal 1210 and having a first width w1and a portion adapted to the input end of the first light emitting diodechip 1301 and having a second width w2. The (n+1)^(th) conductivetransparent connection portion 140 n+1 includes a portion adapted to theoutput terminal 1220 and having a first width w1 and a portion adaptedto the output end of the n^(th) light emitting diode chip 130 n andhaving a second width w2. The other conductive transparent connectionportions between the first conductive transparent connection portion1401 and the (n+1)^(th) conductive transparent connection portion 140n+1 have the second width w2. The first width w1 is determined to belarger than the second width w2.

The two outwardly extending terminals 1001 and 1002 are connected to theinput terminal 1210 and the output terminal 1220, respectively, andprotrude from both sides of the non-conductive transparent substrate.The light transmitting encapsulant 1500 is formed to surround thenon-conductive transparent substrate 1100 and the light emitting diodechips 1300 by molding, completing the fabrication of the light emittingdevice 1000. Only the two outwardly extending terminals 1001 and 1002are uncovered by the light transmitting encapsulant 1500 and are exposedto the outside. The light transmitting encapsulant 1500 may include awavelength conversion material, i.e. a fluorescent material, capable ofproducing white light in concert with the diode chips 1300 emittinglight at blue or ultraviolet wavelengths. At least one light emittingdiode chip capable of emitting light in the wavelength range of 620-680nm may be included in the light emitting diode chips 1300 to convertwhite light to warm white light.

Second Embodiment

FIG. 6 is a partially exploded cross-sectional view of a filament typelight emitting device according to a second embodiment of the presentinvention.

Referring to FIG. 6, the light emitting device 1000 includes anon-conductive transparent substrate 1100 and a plurality of flip-chiptype light emitting diode chips 1300 mounted in a linear array above thenon-conductive transparent substrate 1100, as in the previousembodiment. The light emitting device 1000 includes conductivetransparent connection portions 1403 as connection means formed on thenon-conductive transparent substrate 1100. The conductive transparentconnection portions 1403 connect the adjacent flip-chip type lightemitting diode chips 1300 to each other and connect one of the lightemitting diode chips 1300 to an input terminal and/or an output terminal(not illustrated). The conductive transparent connection portions 1403may be metal oxide films for transparent electrodes, such as ITO films,or transparent metal films formed by deposition to a thickness of 10 μmor less.

As in the previous embodiment, each of the flip-chip type light emittingdiode chips 1300 includes a light transmitting substrate 1311, a firstconductivity type semiconductor layer 1312, an active layer 1313, and asecond conductivity type semiconductor layer 1314 in this order from topto bottom. A portion of the second conductivity type semiconductor layer1314 is connected to a first electrode pad 1321. A portion of the firstconductivity type semiconductor layer 1312 is opened by mesa etching andis connected to a second electrode pad 1341.

The first electrode pad 1321 and the second electrode pad 1341 areconnected to the corresponding conductive transparent connectionportions on the non-conductive transparent substrate 1100 through afirst bump 1322 and a second bump 1342, respectively. The first bump1322 and the first electrode pad 1321 of the flip-chip type lightemitting diode chip 1300 constitute an input end 1320 and the secondbump 1342 and the second electrode pad 1341 of the flip-chip type lightemitting diode chip 1300 constitute an output end 1340. It is noted thatthe input end and the output end may also be interchanged.

In the light emitting device according to the previous embodiment,vacant light transmitting regions are formed without reflectors betweenthe flip-chip type light emitting diode chips and the non-conductivetransparent substrate. In contrast, in the light emitting device 1000according to this embodiment, vacant spaces are formed between the uppersurface of the non-conductive transparent substrate 1100, on which theconductive transparent connection portions 1403 are intermittentlyspaced apart from each other, and the lower surfaces of the flip-chiptype light emitting diode chips 1300, each of which is formed with theinput end 1320 and the output end 1340, and are filled with aninsulating transparent material 1700 to form light transmitting regions.The insulating transparent material 1700 may be, for example, atransparent resin. The insulating transparent material 1700 may includea wavelength conversion material, e.g., a fluorescent material. Thelight emitting device 1000 includes a light transmitting encapsulant1500 in the form of a transparent molding material or a transparenttube. The light transmitting encapsulant 1500 encapsulates the flip-chiptype light emitting diode chips 1300 mounted above the non-conductivetransparent substrate 1100 such that the non-conductive transparentsubstrate 1100, on which the conductive transparent connection portions1403 are formed, is electrically connected to the flip-chip type lightemitting diode chips 1300 through the conductive transparent connectionportions 1403. At least some of the flip-chip type light emitting diodechips 1300 are diode chips emitting light in the blue or ultravioletwavelength band, which produce white light together with the fluorescentmaterial included in the insulating transparent material 1700 and/or thelight transmitting encapsulant 1500. One or more of the light emittingdiode chips 1300 may be diode chips that emit light in the wavelengthrange of 620 to 680 nm, contributing to warm white light emission.

Third Embodiment

FIG. 7 is a partial side cross-sectional view of a filament type lightemitting device according to a third embodiment of the presentinvention.

Referring to FIG. 7, the filament type light emitting device 1000includes a plurality of conductive transparent connection portions 1403made of ITO (hereinafter referred to as “ITO transparent connectionportions”). In order to increase the adhesion between each of the ITOtransparent connection portions 1403 and a bump 1322 of an input end1320 or a bump 1342 of an output end 1340, an opaque metal electrodelayer 1404 is further formed between the ITO transparent connectionportion 1403 and the bump 1322 of the input end 1320 or the bump 1422 ofthe output end 1340 such that it is placed in direct contact with thecorresponding bump 1322 or 1422 on the ITO transparent connectionportion 1403. The other elements are the same as or similar to those inthe previous embodiments and their detailed explanation is omitted.

Fourth Embodiment

FIG. 8 illustrates a filament type light emitting device according to afourth embodiment of the present invention.

Referring to FIG. 8, the filament type light emitting device includes aplurality of light emitting groups G1 and G2, each of which includes nlight emitting diode chips 1300 connected in series on a non-conductivetransparent substrate 1100. The light emitting groups G1 and G2 areconnected in parallel.

In each of the light emitting groups G1 and G2, the n light emittingdiode chips 1300 are connected in series through connection meansincluding conductive transparent connection portions 1401, 1402, 1403, .. . , 140 n, and 140 n 1 between an input terminal 1210 and an outputterminal 1220. The first light emitting diode chip 1301 positionedadjacent to the input terminal 1210 and/or the n^(th) light emittingdiode chip 130 n positioned adjacent to the output terminal 1220 arepreferably diode chips that emit red light at wavelengths of 620 to 680nm. The other light emitting diode chips 1300 are preferably diode chipsthat emit light at blue or ultraviolet wavelengths, which produce whitelight together with a fluorescent material.

Fifth Embodiment

FIG. 9 illustrates a filament type light emitting device according to afifth embodiment of the present invention.

Referring to FIG. 9, the filament type light emitting device includes aplurality of light emitting groups G1 and G2, each of which includes nlight emitting diode chips 1300 connected in series on a non-conductivetransparent substrate 1100. The light emitting groups G1 and G2 areconnected in antiparallel. In each of the light emitting groups G1 andG2, the n light emitting diode chips 1300 are connected in seriesthrough connection means including conductive transparent connectionportions 1401, 1402, 1403, . . . , 140 n, and 140 n 1 between an inputterminal 1210 and an output terminal 1220, as explained in the previousembodiment. The element 1210 acting as the input terminal in the firstlight emitting group G1 becomes an output terminal in the second lightemitting group G2. The element 1220 acting as the output terminal in thefirst light emitting group G1 becomes an input terminal in the secondlight emitting group G2. Although not illustrated, two or more of theconnection portions may be connected to an input or output end of thediode chip emitting light at wavelengths of 620 to 680 nm.

Sixth Embodiment

FIGS. 10 to 13 are views for explaining a light emitting deviceaccording to a sixth embodiment of the present invention.

Referring to FIGS. 10 to 13, the light emitting device 1000 includes afirst substrate 1101 and a second substrate 1102, which are spaced apartfrom and parallel to each other and extend in the lengthwise direction,an input terminal 1210 formed on one end of the first substrate 1101 orthe second substrate 1102, an output terminal 1220 formed on the otherend of the first substrate 1101 or the second substrate 1102, n lightemitting diode chips 1300 mounted above both the first substrate 1101and the second substrate 1102 and arrayed in the lengthwise direction ofthe first substrate 1101 and the second substrate 1102, and connectionmeans 1400 formed on the first substrate 1101 and the second substrate1102 to connect the n light emitting diode chips 1300 in series. Theconnection means 1400 may be a metal film patterned by deposition orplating on the first substrate 1101 and the second substrate 1102. Theinput terminal 1210 and the output terminal 1220 may also be formed onthe first substrate 1101 and/or the second substrate 1102 by depositionor plating for patterning.

The light emitting device 1000 further includes an elongated lighttransmitting encapsulant 1500 that simultaneously covers the lightemitting diode chips 1300 and the first substrate 1101 and the secondsubstrate 1102 above which the light emitting diode chips 1300 aremounted, while allowing exposure of outwardly extending terminals 1001and 1002 protruding from one side of the first substrate 1101 and theother side of the second substrate 1102, respectively. The outwardlyextending terminals 1001 and 1002 may be portions of the input terminal1210 and the output terminal 1220 or may be connected to the inputterminal 1210 and the output terminal 1220, respectively. The lighttransmitting encapsulant 1500 can serve to fix the first substrate 1101to the second substrate 1102.

The light transmitting encapsulant 1500 may be formed by molding atransparent resin and may include a wavelength conversion material, forexample, a fluorescent material, that acts in concert with at least someof the light emitting diode chips 1300, particularly blue light emittingdiode chips 1300, to produce white light.

In this embodiment, the connection means 1400 formed on the firstsubstrate 1101 and the second substrate 1102 is conductive. Theconnection means 1400 includes a first connection portion 1401 formed onthe first substrate 1101 to connect the input terminal 1210 to an inputend 1320 of the first light emitting diode chip 1301, a secondconnection portion 1402 formed on the second substrate 1102 and spacedapart from the first connection portion 1401 to connect an output end1340 of the first light emitting diode chip 1301 to an input end 1320 ofthe second light emitting diode chip 1302, an (n+1)^(th) connectionportion 140 n+1 formed on the second substrate 1102 to connect theoutput terminal 1220 to an output end 1340 of the n^(th) light emittingdiode chip 130 n, and an n^(th) connection portion 140 n formed on thefirst substrate 1101, spaced apart from the (n+1)^(th) connectionportion 140 n+1, and connected to an input end 1320 of the n^(th) lightemitting diode chip 130 n. The connection means 1400 includesintermediate connection portions 1403, . . . , each of which connectsthe two adjacent light emitting diode chips 1300. The adjacentconnection portions 1403 are formed alternately on the first substrate1101 and the second substrate 1102 and are spaced apart from each other.

All connection portions, including the first, second, n^(th), and(n+1)^(th) connection portions (these portions are collectively denotedby numeral “1403”), are spaced apart from each other and are arranged ina zigzag pattern alternately on the first substrate 1101 and the secondsubstrate 1102.

The first substrate 1101 and the second substrate 1102 are spaced apartfrom and parallel to each other to form gaps therebetween. The gaps arelight transmitting regions through which light enters and exits. Each ofthe first substrate 1101 and the second substrate 1102 has flat upperand lower surfaces and is elongated.

In this embodiment, the input terminal 1210 is formed on the uppersurface of one end of the first substrate 1101 and is made of aconductive metal material. The output terminal 1220 is formed on theupper surface of the other end of the second substrate 1102 and is madeof a conductive metal material. In this embodiment, the input terminal1210 and the output terminal 1220 are formed on the differentsubstrates, i.e. the first substrate 1101 and the second substrate 1202,due to the use of the predetermined number (n) of the light emittingdiode chips. If the number of the light emitting diode chips increasedto n+1 or decreased to n−1, both the input terminal 1210 and the outputterminal 1220 may be formed on any one of the first substrate 1101 andthe second substrate 1202. That is, the locations of the input terminal1210 and the output terminal 1220 are determined by the number of thelight emitting diode chips.

The input terminal 1210 and the output terminal 1220 may be connected tothe outwardly extending terminals 1001 and 1002 protruding outward fromthe first substrate 1101 and the second substrate 1102, respectively.The outwardly extending terminals 1001 and 1002 are connected to leadsof external power supply means.

Before or after or simultaneously with the formation of the inputterminal 1210 and the output terminal 1220, the connection means 1400including a conductive metal film pattern, which includes a plurality ofmetal film islands, is provided on the first substrate 1101 and thesecond substrate 1102. The conductive metal film pattern constitutingthe connection means 1400 is formed by forming a conductive metal filmover the entire surfaces of the first substrate 1101 and the secondsubstrate 1102 and etching the conductive metal film through a mask orby arranging a patterned mask on the first substrate 1101 and the secondsubstrate 1102 and forming a conductive metal film on the mask.

The n light emitting diode chips 1300 are arrayed in line along thelengthwise direction of the first substrate 1101 and the secondsubstrate 1102 above both the first substrate 1101 and the secondsubstrate 1102 between the input terminal 1210 and the output terminal1220. The light emitting diode chips 1300 are flip bonding type lightemitting diode chips whose input end 1320 and output end 1340 includeelectrode pads 1321 and 1341 and/or bumps 1322 and 1342, respectively,that extend toward the first substrate 1101 and the second substrate1102.

The n light emitting diode chips 1300 are mounted above the firstsubstrate 1101 and the second substrate 1102 by flip bonding. As aresult of the mounting, the n light emitting diode chips 1300 areconnected to the corresponding conductive transparent connectionportions of the connection means 1400 formed using a conductivetransparent film on the first substrate 1101 and the second substrate1102 such that they are connected in series to form a circuit. In thisembodiment, the conductive transparent connection portions 1401, 1402,1403, . . . , 140 n, and 140 n+1 connect the input terminal to the firstlight emitting diode chip, the output terminal to the last lightemitting diode chip, and the adjacent intermediate light emitting diodechips to each other. This connection eliminates the need for the use ofbonding wires, unlike series circuit connection of conventional lateraltype light emitting diode chips. Between the first substrate 1101 andthe second substrate 1102, gaps exist through which light can betransmitted. Thus, despite their flip-chip type, the light emittingdiode chips 1300 can emit light even in the backward direction. In orderto increase the amount of light emitted backward from the light emittingdiode chips 1300, it is preferred that the light emitting diode chips1300 have a larger width in the transverse direction of the firstsubstrate 1101 and the second substrate 1102 than in the lengthwisedirection of the first substrate 1101 or the second substrate 1102. Itis also preferred that the width of the gap between the first substrate1101 and the second substrate 1102 is larger than the widths of thefirst substrate 1101 and the second substrate 1102.

Each of the light emitting diode chips 1300 includes a lighttransmitting substrate 1311, a first conductivity type semiconductorlayer 1312, an active layer 1313, and a second conductivity typesemiconductor layer 1314 in this order from top to bottom. A portion ofthe second conductivity type semiconductor layer 1314 is connected tothe first electrode pad 1321. A portion of the first conductivity typesemiconductor layer 1312 is opened by mesa etching and is connected tothe second electrode pad 1341.

The first electrode pad 1321 and the second electrode pad 1341 areconnected to the conductive transparent connection portion 1401, 1401,1402, 1403, . . . , 140 n or 140 n+1 on the first substrate 1101 and/orthe second substrate 1102 through the first bump 1322 and the secondbump 1342, respectively.

Although not illustrated, the formation of an extension on each of thefirst electrode pad 1321 and the second electrode pad 1341 may beconsidered. The extension may be formed integrally with or separatelyfrom each of the first electrode pad 1321 and the second electrode pad1341. Due to the formation of the extensions, the first electrode pad1321 and the second electrode pad 1341 ensure reliable and easyconnection to the first substrate 1101 and the second substrate 1102,respectively.

The addition of the extensions increases the contact areas of the firstelectrode pad 1321 and the second electrode pad 1341 with the first bump1322 and the second bump 1342, respectively, resulting in larger contactareas of the first bump 1322 and the second bump 1342 with the firstsubstrate 1101 and the second substrate 1102, respectively. Anadditional light transmitting material may be interposed between thefirst and second substrates 1101 and 1102 and the light emitting diodechips 1300 before formation of the encapsulant. In this case, stablecontact may be achieved between the light emitting diode chips 1300 andthe first and second substrates 1101 and 1102 without substantialinterference with backward light emission from the light emitting diodechips 1300.

It is preferred that the input terminal 1210 includes a metal basematerial 1211 including at least one of Ag, Au, Cu, and Al and areflective material film coated on the metal base material. Likewise, itis preferred that the output terminal 1220 includes a metal basematerial including at least one of Ag, Au, Cu, and Al and a reflectivematerial film coated on the metal base material.

The light emitting device 1000 is fabricated by the following procedure.First, the first substrate 1101 and the second substrate 1102 or a basematerial including the first substrate and the second substrate areprepared. A metal or a conductive metal compound is deposited on thefirst substrate and the second substrate or the base material to form aconductive transparent film. Then, the conductive transparent film isetched to form the connection means 1400 including conductivetransparent connection portions 1401, 1402, 1403, . . . , 140 n, and 140n+1 on the first substrate 1101 and the second substrate 1102.Alternatively, the connection means 1400 including conductivetransparent connection portions 1401, 1402, 1403, . . . , 140 n, and 140n+1 may be formed by forming a patterned mask on the first substrate andthe second substrate and depositing a conductive metal compound or ametal thereon. An E-beam or sputtering process may be used for theformation of the connection means 1400.

Next, the input terminal 1210 and the output terminal 1220 are arrangedon the first substrate 1101 and the second substrate 1102, respectively,such that they are electrically connected in series with the lightemitting diode chips 1300 through the conductive transparent connectionportions 1401, 1402, 1403, . . . , 140 n, and 140 n+1.

With this arrangement, the input terminal 1210 is connected to the inputend 1320 of the first light emitting diode chip 1301 through the firstconductive transparent connection portion 1401, the output end 1340 ofthe first light emitting diode chip 1301 is connected to the input end1320 of the second light emitting diode chip 1302 through the secondconductive transparent connection portion 1402, the output terminal 1220is connected to the output end 1340 of the n^(th) light emitting diodechip 130 n through the (n+1)^(th) conductive transparent connectionportion 140 n+1, and the n^(th) conductive transparent connectionportion 140 n is connected to the input end 1320 of the n^(th) lightemitting diode chip 130 n. In addition, the other adjacent lightemitting diode chips 1300 are connected to each other through thecorresponding conductive transparent connection portions.

The two outwardly extending terminals 1001 and 1002 are connected to theinput terminal 1210 and the output terminal 1220, respectively, andprotrude from one side of the first substrate 1101 and the other side ofthe second substrate 1102, respectively. The light transmittingencapsulant 1500 is formed to surround the first substrate 1101, thesecond substrate 1102, and the light emitting diode chips 1300 bymolding, completing the fabrication of the light emitting device 1000.Only the two outwardly extending terminals 1001 and 1002 are uncoveredby the light transmitting encapsulant 1500 and are exposed to theoutside. The light transmitting encapsulant 1500 may include awavelength conversion material, i.e. a fluorescent material, capable ofproducing white light in concert with the diode chips 1300 emittinglight at blue or ultraviolet wavelengths. At least one light emittingdiode chip capable of emitting light in the wavelength range of 620-680nm may be included in the light emitting diode chips 1300 to convertwhite light to warm white light.

Seventh Embodiment

FIGS. 14 and 15 are views for explaining a light emitting deviceaccording to a seventh embodiment of the present invention.

Referring to FIGS. 14 and 15, an elongated conductive electrode withoutinterruption is provided on a first substrate 1101 and an elongatedconductive electrode without interruption is provided on a secondsubstrate 1102. The conductive electrodes are connection means forelectrical connection of light emitting diode chips 1300. The firstsubstrate 1101 may be in the form of a metal plate or may be made byforming an elongated linear conductive pattern without interruption on anon-conductive substrate. Likewise, the second substrate 1102 may be inthe form of a metal plate or may be made by forming an elongated linearconductive pattern without interruption on a non-conductive substrate.Thus, the first substrate 1101 can act as a common electrode to whichall input ends of the light emitting diode chips 1300 are connected andthe second substrate 1102 can act as a common electrode to which alloutput ends of the light emitting diode chips 1300 are connected.

In this embodiment, each of the light emitting diode chips 1300 is aflip bonding type light emitting diode chip and includes an input end1320 and an output end 1340 extending toward the non-conductivetransparent substrate 1100. The light emitting diode chips 1300 aremounted above both the first substrate 1101 and the second substrate1102 spaced apart from each other and are arrayed along the lengthwisedirection of the first substrate 1101 and the second substrate 1102. Thefirst substrate 1101 is formed as a first electrode connected to allinput ends 1320 of the light emitting diode chips 1300 and the secondsubstrate 1102 is formed as a second electrode connected to all outputends 1340 of the light emitting diode chips 1300. With this arrangement,the light emitting diode chips 1300 are connected in parallel.

The other elements are the same as or similar to those in the previousembodiments.

What is claimed is:
 1. A light emitting device comprising: a non-conductive transparent substrate; one or more light emitting diode chips mounted on the upper surface of the non-conductive transparent substrate and each comprising input and output ends extending toward the non-conductive transparent substrate; and conductive transparent connection portions formed on the upper surface of the non-conductive transparent substrate and electrically connected to the input and output ends, wherein light transmitting regions are provided in the vicinity of the input and output ends between the non-conductive transparent substrate and the light emitting diode chips and light is emitted backward from the light emitting diode chips through the light transmitting regions and the non-conductive transparent substrate.
 2. The light emitting device according to claim 1, wherein each of the input end and the output end comprises an electrode pad and a bump that extend toward the non-conductive transparent substrate.
 3. The light emitting device according to claim 1, wherein the light transmitting regions are formed by filling an insulating transparent material in vacant spaces between the non-conductive transparent substrate and the light emitting diode chips.
 4. The light emitting device according to claim 3, wherein the insulating transparent material comprises a fluorescent material.
 5. The light emitting device according to claim 1, further comprising a light transmitting encapsulant encapsulating the non-conductive transparent substrate and the light emitting diode chips.
 6. The light emitting device according to claim 1, wherein the one or more light emitting diode chips comprise n light emitting diode chips arrayed on the non-conductive transparent substrate and the n light emitting diode chips are connected in series through the conductive transparent connection portions on the non-conductive transparent substrate.
 7. The light emitting device according to claim 1, wherein a metal electrode layer is interposed between each of the conductive transparent connection portion and a bump of the input end or a bump of the output end.
 8. The light emitting device according to claim 1, wherein the amount of light emitted through the non-conductive transparent substrate is larger than that of light emitted in a direction opposite to the direction toward the non-conductive transparent substrate.
 9. A light emitting device comprising: an elongated non-conductive transparent substrate; an input terminal arranged on one side of the non-conductive transparent substrate; an output terminal arranged on the other side of the non-conductive transparent substrate; n light emitting diode chips arrayed above the non-conductive transparent substrate and each having input and output ends; and connection means formed on the non-conductive transparent substrate to connect the n light emitting diode chips in series, wherein the connection means comprises a first connection portion that connects the input terminal to the input end of the first light emitting diode chip and is made of a conductive transparent material.
 10. The light emitting device according to claim 9, wherein each of the input end and the output end comprises an electrode pad extending toward the non-conductive transparent substrate.
 11. The light emitting device according to claim 9, wherein the connection means further comprises a second connection portion spaced apart from the first connection portion and connected to the output end of the first light emitting diode chip, and the second connection portion is made of a conductive transparent material.
 12. The light emitting device according to claim 11, wherein the second connection portion is connected to the input end of the second light emitting diode chip.
 13. The light emitting device according to claim 9, wherein the connection means comprises an (n+1)^(th) connection portion connecting the output terminal to the output end of the n^(th) light emitting diode chip, and the (n+1)^(th) connection portion is made of a conductive transparent material.
 14. The light emitting device according to claim 9, wherein the connection means further comprises an n^(th) connection portion spaced apart from the (n+1)^(th) connection portion and connected to the input end of the n^(th) light emitting diode chip, and the n^(th) connection portion is made of a conductive transparent material.
 15. The light emitting device according to claim 9, wherein the connection means comprises connection portions connecting the adjacent light emitting diode chips and the connection portions are made of a conductive transparent material.
 16. A light emitting device comprising: an elongated first substrate; an elongated second substrate spaced apart from and parallel to the first substrate; connection means provided between the first substrate and the second substrate and made of a conductive material; and n light emitting diode chips mounted on both the first substrate and the second substrate and electrically interconnected through input and output ends connected to the connection means, wherein gaps are formed between the first substrate and the second substrate to allow light from the n light emitting diode chips to pass therethrough.
 17. The light emitting device according to claim 16, further comprising a light transmitting encapsulant that covers the n light emitting diode chips, the first substrate, and the second substrate.
 18. The light emitting device according to claim 16, further comprising an input terminal formed on one end of the first substrate and an output terminal formed on the other end of the first substrate or the second substrate.
 19. The light emitting device according to claim 16, wherein the connection means is formed on the first substrate or the second substrate and comprises connection portions connecting the input and output ends of the adjacent light emitting diode chips.
 20. The light emitting device according to claim 16, wherein the connection means comprises a first electrode made of a conductive material on the first substrate and to which all input ends of the n light emitting diode chips are connected and a second electrode made of a conductive material on the second substrate and to which all output ends of the n light emitting diode chips are connected. 